Revert "Fix 'error 9 while decompressing xz file'"

This reverts commit 78fa47a7f0.

src/libutil/retry.hh

@@ -1,38 +0,0 @@
-#pragma once
-
-#include "logging.hh"
-
-#include <functional>
-#include <cmath>
-#include <random>
-#include <thread>
-
-namespace nix {
-
-inline unsigned int retrySleepTime(unsigned int attempt)
-{
-    std::random_device rd;
-    std::mt19937 mt19937;
-    return 250.0 * std::pow(2.0f,
-        attempt - 1 + std::uniform_real_distribution<>(0.0, 0.5)(mt19937));
-}
-
-template<typename C>
-C retry(unsigned int attempts, std::function<C()> && f)
-{
-    unsigned int attempt = 0;
-    while (true) {
-        try {
-            return f();
-        } catch (BaseError & e) {
-            ++attempt;
-            if (attempt >= attempts || !e.isTransient())
-                throw;
-            auto ms = retrySleepTime(attempt);
-            warn("%s; retrying in %d ms", e.what(), ms);
-            std::this_thread::sleep_for(std::chrono::milliseconds(ms));
-        }
-    }
-}
-
-}

src/libutil/types.hh

@@ -109,8 +109,6 @@ public:
     const string & msg() const { return err; }
     const string & prefix() const { return prefix_; }
     BaseError & addPrefix(const FormatOrString & fs);
-
-    virtual bool isTransient() { return false; }
 };
 
 #define MakeError(newClass, superClass) \